Earth Sciences Report 1978-05

Earth Sciences Report 1978-05

Hydrogeology of the southwest segment, Edmonton, Alberta

The southwest quarter of the Edmonton map area (NTS 83H) has an area of about 2850 square km (1100 square mi.). Climate is microthermal with warm summers, and the area receives about 460 mm (18 in) of precipitation annually.

In the area thin drift primarily of glacial origin, overlies Tertiary and Cretaceous bedrock. The Paskapoo Formation, which is capable of yielding up to 38 l/sec (500 igpm), is the best bedrock aquifer. Basal deposits of sand known as the Saskatchewan gravels and sands, and located within the preglacial Stony Valley, are the best aquifer in the surficial deposits; these deposits are capable of yielding up to 8 l/sec (100 igpm).

The dominant direction of groundwater flow is from the upland areas toward the Stony Valley and North Saskatchewan River.

Drift waters are predominantly of the calcium-magnesium type with a total dissolved solids concentration of usually less than 1500 mg/l. To the depths considered, sodium bicarbonate type water is the dominant bedrock water type. Highly mineralized groundwaters, associated with total dissolved solids concentrations as high as 5000 mg/l and of the chloride or sulfate type, are found locally in the northeast corner of the study area.